1. Field of the Invention
The present invention relates to a plasmon resonance structure body, and more specifically, it relates to a method of controlling the plasmon resonance thereof.
2. Background Art
In the near-field optics, the utilization of electric-field enhancement effect is conceived, and studies are being made on its application to various fields such as telecommunication, recording media, or the like (see non-patent reference 1 below). The electric-field enhancement effect can be realized by forming fine particles several to several hundred nanometers in size (which are referred to simply hereinafter as “nano-sized fine particles”), and by using the localized surface plasmon that generates in the vicinity thereof. The nano-sized fine particles can be formed generally by a chemical method, for example, a sol-gel process, and are used in a three-dimensionally dispersed state in a film. FIG. 4 shows an example comprising nano-sized metallic fine particles 902 dispersed randomly in the dielectric film 900.
Non-patent reference 1: OYO-BUTURI, Vol. 73, No. 10 (2004) “Propagation and control of surface plasma polariton”, pp. 1275-84.
It is known that, when light is incident to nano-sized fine particles from the thickness direction of a film, localized surface plasmon is distributed in the direction orthogonal to the light. Accordingly, in order to control the localized surface plasmon, different modes, i.e., in the thickness direction and inside the plane orthogonal to the thickness direction, must be taken into consideration. However, the plasmon resonance structure body obtained by the chemical process above is in such a state that nano-sized fine particles are randomly distributed in three dimensions; hence, the plasmon resonance cannot be controlled for independent modes in the film thickness direction and in the direction orthogonal thereto. Accordingly, it has been unfeasible to achieve efficient improvement on the plasmon enhanced electric-field effect.